1. Field of the Invention
The present invention relates to a disk drive including a case body, and a main-body portion and a circuit board both disposed within the case body.
2. Description of Related Art
There have been conventionally and widely utilized disk drives for reproducing a piece of information from or recording/reproducing a piece of information into/from an optical disk such as a DVD (Digital Versatile Disk) or Compact Disc. Such disk drives are known to have a constitution exemplarily shown in FIG. 6.
FIG. 6 shows a disk drive 101 having a case body 102 made of metal in an approximately box-like shape opened at one face. Disposed within the case body 102 is an approximately parallelepiped frame body 103 having rigidity and made of synthetic resin. Disposed in the frame body 103 are: disk rotating driver 104 for rotating an optical disk; reproducer 105 having an optical sensor for recording a piece of information into or reproducing the piece of information recorded in the optical disk; and a main-body portion 106 having moving structure (not shown) for moving the reproducer 105 relative to the optical disk. Further, disposed in the frame body 103 is a disk tray (not shown) for placing the optical disk thereon and capable of moving through the opened one face of the case body 102 in a manner capable of advancing and retracting. Disposed on the frame body 103 is a cooling fan 108.
Disposed within the case body 102 is a circuit board 112 equipped with a controlling circuit having electrical components 111 for controlling the operation of the main-body portion 106. This circuit board 112 is mounted on a bottom lower surface of the frame body 103 which surface is reverse to the bottom upper surface of the frame body 103 provided with the main-body portion 106, in a state that the circuit board 112 covers substantially the whole of the bottom lower surface of the frame body 103. The circuit board 112 is also disposed in a state that the surface of the circuit board 112 provided with the electrical components 111 having particularly higher heat release values is disposed to oppose to the bottom inner or upper surface of the case body 102 at a predetermined clearance. Note, the circuit board 112 is also disposed to oppose to the bottom lower surface of the frame body 103 at another predetermined clearance. Mounted on the bottom inner surface of the case body 102 are heat radiating members 116 such as made of silicone rubber having thermal conductivity and electrical insulation ability so as to be closely contacted with the electrical components 111 having particularly higher heat release values.
The heat-generating electrical components 111 of the circuit board 112 are cooled, since the generated heat is conducted to the case body 102 via heat radiating members 116. Further, driving the cooling fan 108 sucks air from a gap of the case body 102 and then through between the circuit board 112 and frame body 103 toward the cooling fan 108, and the air heat-exchanged with the circuit board 112 is discharged as an exhaust airstream to the exterior of the case body 102 to thereby cool the circuit board 112. Note, the air flowed by driving the cooling fan 108 never flows into the main-body portion 106 isolated therefrom by a covering plate 103a provided on the frame body 103, thereby avoiding that the operation of the main-body portion 106 is obstructed by dust and dirt included in the flowing air.
However, in the disk drive 101 having the structure shown in FIG. 6, the electrical components 111 having particularly higher heat release values are arranged on that lower surface of the circuit board 112 which opposes to the case body 102, because the electrical components 111 are required to forcibly radiate heat to the case body 102. As such, the fresh or outside air flowing along the upper surface of the circuit board 112 opposing to the frame body 103 fails to efficiently contact with the electrical components 111, so that the electrical components 111 are not efficiently cooled. Thus, the electrical components 111 having particularly higher heat release values are not sufficiently cooled, thereby possibly causing a problem that the temperature within the disk drive 101 is raised such that the driving performances of the main-body portion 106 and a disk are exposed to thermal loads, to thereby lower the tolerances of the driving performances against temperature.